染色体交换

An increased incidence of sister chromatid exchanges in peripheral lymphocytes of operating room personnel exposed to waste anesthetic gases has been reported.

已有报道，在暴露于麻醉性气体的手术室工作人员中，外周淋巴细胞姐妹染色体交换的发生率有所上升。

But this prohibition has caused most of the genes on the Y chromosome to decay for lack of fitness.

这种禁止也导致Y 染色体上的大多数基因退化，在其它的基因组上，被损坏的基因可以通过与另外的染色体交换而除去。

It is expected that hyg would be integrated stablely into the chromosome along with insert while spc/str would be lost during the second cross-over. Gene replacement through these two flanking sequences will result in the susceptibility of the transformants to phage φHAU3, which provides an enrichment for desired transformants by counterselection.

预期在携带有大插入片段的基因置换YAC分子进入野生型变铅青链霉菌后，YAC分子将通过1.4kb或1.0kb片段与染色体发生同源单交换，继而发生同源双交换，hyg连同大插入片段一起稳定地整合到染色体上，而spc／str丢失，从而导致菌株Hyg〓Str〓的表型。

The results showed that all of them could detect the presence of ZFY DNA sequences except a 46 XX"male"and a 46 XX hermaphrodite, our findings confirmed that Ferguson-Smith〔1966〕 forwarded the hypothesis that the X-Y intercharge model for XX maleness can be regarded as an abnormal exchange initaited in a region proximal to TDF and extending to the telomere,and,also strongly suggested that ZFY gene palyed an important role in sex determining of human.

结果除一例46XX两性畸形，一例46XX&男性&外，余均能检测到ZFY DNA序列(ZFY DNA序列存在于46XX真两性畸形和45XO Turner's综合症，在国内外尚未见报道)。证实了1966年，Ferguson-Smith提出的理论：在父源减数分裂期间，X-Y发生不等交换，导致Y染色体DNA插入性易位。XX男性是由于Y染色体上的TDF基因转移至X染色体上所致。

Compared the similarity and difference of distribution of homologous fragments on X and Y, we suggested that the sex chromosomes of spiny eel have evolved from a pair of homologous ancestral chromosomes, and during the evolution, a pericentric inversion might have occurred on the original Y chromosome, and subsequently terminal regional duplication might have followed, eventually resulting in the differentiation and formation of X and Y chromosomes, then the recombinants between sex chromosomes were repressed, so the sex chromosomes could be inherited steadily.

根据X、Y染色体上同源片段的分布的相似和相异，我们对刺鳅性染色体的分化历程进行了推测，即：刺鳅的性染色体起源于一对原始的同源染色体，通过原Y染色体上的一个明显的臂间倒位，以及染色体末端的异染色质成分的扩增，导致原始Y染色体与X染色体在染色体结构上的分化，从而抑制了X、Y性染色体之间的遗传物质的重组交换，为性染色体的稳定遗传奠定了基础。

The results showed that: at metaphase I, the homoeologous chromosome pairing among different F1 hybrids ranged from 2.0 to 11.4 bi-valents formed by homoeologous chromosomes per pollen mother cell, and very few multivalents, and even very few bivalents were formed by two chromosomes within one genome rather than homoeologous chromosomes in some PMCs; at anaphase I, all biva-lents were disjoined and most univalents were divided.

结果表明在中期I阶段，这些杂种一代的近缘染色体联会变化很大，每个花粉母细胞中二价体形成的数目从平均2个到11.4个不等，甚至在某些花粉母细胞中，还发现极少的多价体和非部分同源染色体所形成的单基因组内二价体；在后期I时，所有的二价体分离，同时多数单价体也分离，分离的二价体和分离的单价体都移向两极，从而形成两组染色体；因为这时完整花粉母细胞中分离的二价体在两组染色体中总是对应出现，从而根据半二价体上染色体重组的位置可以分析在二价体的四分体时期发生在非姊妹染色体之间的多种染色体交换类型，如单交换、三线双交换、四线双交换、四线三交换和四线多交换。

The crossover operation in the traditional GA operating is that choose two chromosome cross only at random also you can cross a bit, match and cross partly, cross order and cross cycle etc.

传统GA算法中的交叉操作，是随机选取两个染色体进行单点交叉(也可以多点交叉、部分匹配交叉、顺序交叉和周期交叉等等)，但是不管是采用何种交叉操作，新的子代染色体某一基因位上的值都是由两个父代染色体中相应基因位值经过一定交叉运算(直接交换或经算术运算等)所得到的，采用这种交叉算子操作使群体经过多次迭代后群体中的个体开始出现极大的相似性，因此照此下去就会出现早期收敛现象，使得算法的收敛速度非常慢甚至只能求到问题的局部最优解。

The crossover operation in the traditional GA operating is that choose two chromosome cross only at random also you can cross a bit, match and cross partly, cross order and cross cycle etc.

传统GA算法中的交*操作，是随机选取两个染色体进行单点交*(也可以多点交*、部分匹配交*、顺序交*和周期交*等等)，但是不管是采用何种交*操作，新的子代染色体某一基因位上的值都是由两个父代染色体中相应基因位值经过一定交*运算(直接交换或经算术运算等)所得到的，采用这种交*算子操作使群体经过多次迭代后群体中的个体开始出现极大的相似性，因此照此下去就会出现早期收敛现象，使得算法的收敛速度非常慢甚至只能求到问题的局部最优解。

The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over.

染色体交叉在减数分裂过程中成对的染色体之间的接触点产生一种交叉形状的构造，代表着基因互相交换的细胞表现形式

YR-cohesion chromosome model will give a better answer to the questions such as exchange,centromere,holocentromere,synaptonemal complex,polytene chromosome,puff,lampbrush chromosome,chromosome banding,non-segregation of sister chromatid,pollentube pathway and biological evolution.

YR-染色体模型能自然、合理地解释所有遗传现象，如交换、着丝粒、全身着丝粒或弥散型着丝粒染色体、同源染色体联会及联会复合体的中央区、多线染色体与膨突、灯刷染色体、染色体分带、姊妹染色体由前期到中期不分开、花粉管会导入外源遗传物质、高等生命是怎样从原始生物进化而来的等等。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。